Upright vacuum cleaners are a particularly popular type of vacuum cleaner for household and light industrial vacuum cleaning of floors and floor carpeting. Typically, the unit includes a cleaner head assembly mounted on wheels and having a suction generator/motor assembly and a motor driven roller agitator or roller brush mounted on the chassis. The operating handle is pivoted to the chassis and can be placed in a lower inclined position to assist the operator in moving the vacuum cleaner over the carpet, and an upright position whereby the vacuum cleaner can be conveniently stored in a closet or the like and occupying minimal space. A filter bag is generally mounted on the handle within a hard case or a flexible fabric bag with the filter bag communicating with a suction passage within the chassis to collect the dirt-ladened air brought up from the floor or carpet. The handle may also carry a storage rack, e.g. for the electric cord providing power to the cleaner, and for other accessories.
Commonly, the cleaner head assembly includes an adjustment knob, or foot-actuated lever, for adjusting the height of the chassis, and thus the roller brush or agitator, relative to the floor.
Some upright vacuum cleaners also include a structural arrangement whereby the on-the-floor vacuum cleaning operation can be interrupted to provide for suction cleaning off-the-floor, such as cleaning venetian blinds or kick moldings about the floor, or chairs and other items of furniture and the like. An attachment hose is provided having an inlet which may be connected to the suction source or passageway communicating with the suction generating device. It is known, for example, to provide a separate attachment device over the front of the vacuum cleaner in the area of the agitator with the suction hose leading off of the device, as shown in U.S. Pat. No. 3,955,237. Storage of the device can be troublesome to the user, and the system necessitates passing the dirt-laden air over the agitator or roller brush, thus disturbing the efficiency of the system.
It is also known to provide means for blocking the air passageway between the agitator and the suction generating device and placing downstream of the blockage an auxiliary inlet port for attaching a suction-type attachment hose. Such systems require manually adjusting the blockage, e.g. a sliding door, from the open position to the closed position, and then manually opening the door when the vacuum cleaner is to be converted to on-the-floor use.
Further, with such known systems, it is necessary to disturb the floor height setting by manually adjusting the chassis height relative to the floor or asix of the rollers upon which it is moved across the floor to a position of maximum height and then beyond to fully lift the agitator free of any carpeting or floor. Thus, when the vacuum cleaner is returned to on-the-floor use, the floor height adjustment must again be manually adjusted to the preferred setting.
With known height adjusting structures, it is also common that the mechanism include a single cam on the chassis and cam follower located on an axial retainer member carrying the forwardmost rollers of the cleaner head assembly. Thus, with the chassis supported by two laterally spaced rollers or casters at the rear, i.e. one at each end of a rear axle member, and with the forward end of the chassis supported only at a single point upon which the height adjusting cam member rests on the cam follower, the cleaner head assembly is likely to feel to the operator slightly unsteady as it is permitted to rock about a swing axis extending longitudinally of the vacuum cleaner from front to rear and passing through the single support point defined by the height adjusting member.